Megafaunal distribution and biodiversity in a heterogeneous landscape: the iceberg-scoured Rockall Bank, NE Atlantic

Abstract

Species distributions are influenced by spatial structure in environmental factors, but the scales at which these dependencies occur and the effect of habitat patch diversity, connectivity and spatial arrangement have rarely been investigated in deep-sea settings. In this study, spatially limited photographic transects collected from Rockall Bank, NE Atlantic, were combined with sidescan and multibeam sonar maps to model spatial patterns in species distribution and biodiversity. Sediment interpretation maps were created and canonical ordination techniques were used to examine relationships between fine-scale sediment characteristics extracted from the digital stills as well as landscape metrics describing the patch mosaic structure of the surrounding areas. Fine-scale sediment characteristics explained 45.1 and 63.8% of the variation in species composition and biodiversity, respectively. This survey effectively captured variation in species distribution resulting from iceberg ploughmarks, occurring at a scale of < 50 m -which would normally go undetected by traditional ship-based studies. Our study suggests that fine-scale environmental information is required to capture the spatial heterogeneity of complex seafloor areas in sufficient detail to model species distributions and biodiversity.

Environmental factors structuring Arctic megabenthos—a case study from a shelf and two fjords

“…Between fjords, stone size heterogeneity only explained a small fraction (3%) of the variability in the biotic data. While it is possible that habitat heterogeneity influences benthic megafauna on a larger spatial scale than was quantified here (approximately 40 m; Robert et al, 2014), it was not possible to quantify habitat heterogeneity on larger spatial scales in this case study. Nevertheless, our results do highlight the importance of considering habitat heterogeneity on different spatial scales.…”

“…The interplay between regional-and local-scale factors is an important determinant of diversity in biotic communities (Ricklefs, 1987), and marine benthic diversity can be influenced by factors at a variety of spatial scales (Gutt and Piepenburg, 2003;Gage, 2004;Robert et al, 2014). In the Arctic, environmental drivers such as depth, benthic food supply, and bottom oxygen affect megabenthic communities at regional scales, but factors such as substratum type and disturbance may be just as important in structuring communities on more local scales (Kuklinski et al, 2006a;Roy et al, 2014).…”

Detailed Mapping of Hydrothermal Vent Fauna: A 3D Reconstruction Approach Based on Video Imagery

“…The statistically classified faunal assemblages were tested for indicator species as well using the "IndVal.g" function in R (modified after Robert et al, 2014).…”

Community composition of epibenthic megafauna on the West Greenland Shelf

“…The implications of aggregation at such a coarse taxonomic resolution should be kept in mind when interpreting the results presented herein. However, the use of higher taxonomic levels as biodiversity indices is suited to investigating broader-scale patterns (Robert et al 2014) and the wide geographic spread of this analysis is concordant with examining this broad scale.…”